An aerial view of the new Apple data center in Maiden, North Carolina.

The environmental group Greenpeace has identified Apple as the leading offender in using energy from "dirty" sources to power its data centers, including coal and nuclear power. The group's finding relies almost entirely on the impact of the company's huge new data center in Maiden, North Carolina.

"The $1 Billion Apple iData Center in North Carolina, expected to open this spring, will consume as much as 100 MW of electricity, equivalent to the electricity usage of approximately 80,000 homes in the U.S. or over a quarter million in the E.U.," Greenpeace writes in a report released Thursday and timed to Earth Day. "The surrounding energy grid has less than 5 percent clean energy, with the remaining 95 percent coming from dirty, dangerous sources like coal and nuclear."

But the group's scorecard raises questions about whether Greenpeace is gauging the actual impact of working data center facilities, or focusing on the companies that may generate the most headlines. The iDataCenter has been the focus of intense speculation in the IT press and Mac enthusiast sites. Greenpeace's focus on Apple was noted in headlines Thursday by CNN, Time, The Washington Post, PC World, Barrons, The Independent, The Atlantic, The Guardian and the Huffington Post.

Apple Mum on Power Usage

The problem: It's not clear that Apple has even begun operating its North Carolina facility. Since Apple would likely scale its operations gradually, it could be years before the facility is using anywhere near the power capacity attributed to it by Greenpeace. And is the iDataCenter really wired for 100 megawatts, a number 33 percent beyond the capacity cited for any other data center cited in the Greenpeace study?

"As far as I know, there's no known user on the planet that uses that much power in a single location," said Scott Millar, director of the Catawba County Economic Development Corporation. Millar said Apple has not disclosed its planned power usage at its site in Maiden, which is in Catawba County.

Greenpeace's Gary Cook said the group contacted Apple, but the company declined to discuss its power usage. Cook said the 100 megawatt estimate was developed based upon Apple's stated investment of $1 billion and standard building costs for data center capacity.

Cook emphasized that although Greenpeace highlighted Apple's energy use and power mix in its new report (How Dirty is Your Data?), the group is not focusing a specific campaign designed to influence the company's data center site selection, as it has with its "Unfriend Dirty Coal" media initiative targeting Facebook.

'Dirty Data Triangle'

But the Greenpeace report was sharply critical of the presence of Apple, Google and Facebook in North Carolina, which it labeled the "dirty data triangle."

"These mega data centers, which will draw from some of the dirtiest generation mixes in the US, highlights the sway of low-cost energy, misplaced tax incentives, and a corresponding lack of commitment to clean energy," Greenpeace writes.

Greenpeace objects to coal because of its impact on the environment, and opposes nuclear energy “because of its unacceptable risk to the environment and human health.” The group says expansion of nuclear power should be halted, and calls for the shutdown of all existing nuclear power plants.

Millar said Duke Energy, the local utility, currently sources 52 percent of its energy in the Carolinas from nuclear power, 37 percent from fossil fuels, and 7 percent from forms of hydro-electric power.